HINTS:
– try to shoot them one by one but fast – gives you x2, x3 and so on
- there is “No repair” bonus
- invaders moves in formations
- if you break the formation too far they will try to get away
- if you break the formation too close the invaders will become berserks
- plasma cannon bullets are self-targeting, but when there are no targets these bullets will go to the position where your mouse was when you fired
- think of using previous hints and… something else